package top.seefly.javase.old2017.mypraxis;

public class SwapDemo {
    
    public static void main(String[] args) {//I can not do that
        int a = 4;
        int b = 5;
        swap(a, b);
        System.out.println(a + "" + b);
    }
    
    public static void swap(Integer a, Integer b) {
        a = 10;
        b = 15;
    }
}

